Relieving slide-valves from the pressure of steam



UNITED STAES ENT OFFICE.

WILLIAM BUR-DON, OF BROOKLYN, NEW YORK.

RELIEVING- SLIDE-VALVES FROM THE PRESSURE OF STEAM.

To all wh-0m t may concern:

Be it known that I, VILLIAM BURDON, of the city of Brooklyn, in the county of Kings and State of New York, have invented a new and Improved Means of Relieving Slide-Valves of Steam-Engines of Unnecessary Pressure; and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming a part of this specification, in which- Figure l, exhibits a longitudinal section of a steam chest and slide valve with my invention applied. Fig. 2, exhibits a transverse section of the steam-chest and a portion of t-he device by which the valve is relieved of pressure, but shows the valve and its immediate appendages entire.

Similar letters of reference indicate corresponding parts in both figures.

This invention consists in a hollow cylinder placed within the steam chest and supported upon wheels to run on the valve seat or on suitable ways within the steam chest parallel therewith, said cylinder being arranged with its axis perpendicular to the valve seat and being open at the end next the valve seat to receive a piston attached rigidly to the valve, but being closed at the oppo-site end. This piston is of such size as only to leave exposed to the pressure of the steam, a portion of the valve of an area suiicient to receive the amount of pressure requisite to confine the valve to its seat and therefore as it is fitted steam tight to the cylinder, it causes the unnecessary pressure that would come on the valve to be received by the head of the cylindler `and tra-ns- Initted thereby to the wheels, which, as the valve is moved back and forth, roll upon the seat or ways and produce scarcely any friction.

To enable thost skilled in the art to make and use my invention, I will proceed to describe it with reference to the drawings.

I-I, is the steam chest; B, is the valve seat and A, the slide valve. The valve face and seat may be of the usual or any known construction. C is the piston which may be Speccation of Letters Patent No. 14,999, dated June 3, 1856.

cast with or otherwise suitably attached to the valve. It is turned up truly cylindrical and smoothly and may, if desired, be packed like the working piston of a steam engine, but I do not consider that packing will be essential.

E, is the hollow cylinder open at the end next the valve seat and closed at the opposite end Z). This may be of brass or iron.

F, F, are the wheels upon which the cylinder travels, which may be fitted to axles c, 0, cast with the cylinder D, or attached to it in any other suitable manner to stand parallel with the valve seat so that the cylinder will travel over the valve seat with its axis perpendicular thereto. The cylinder is bored parallel and smoothly to receive the piston C, which should it it perfectly steam tight. It may have two pairs of wheels as represented, but one pair may be suflicient as it will be kept in proper position by the piston. Motion may be given to the valve in the usual manner by a stem attached either to itself or to the cylinder.

It will be understood by reference to the drawing, that the valve piston C litt-ing steam tight to the cylinder E, and the back of the cylinder being closed at b, prevents any steam acting upon the back of the valve except on the narrow margin a, a, which is left outside of the piston. This is just suflicient to receive the requisite amount of pressure to keep the valve tight. The valve will always lind its place on the seat and its .wear will be compensated for by the action of the steam 0n the margin a, a., by which means the piston will always be forced as far as possible out of the cylinder.

The only motion of the piston in the cylinder when the valve is once set in operation will be what may be necessary to compensate for any irregularity of the wheels or the ways on which they run or for the wear of the valve and seat which of course will be scarcely perceptible. In order to guard effectually against any escape of steam between the piston C and the cylinder D,I drill a small hole, e, (see Fig. l.) through the center of the piston to establish a constant communication between the back part of the cylinder and the eXhaust port j", so that no steam can accumulate behind the piston to create a pressure.

What I claim as my invention and desire 5 to secure by Letters Patent, is-

The employment of a hollow cylinder E, With a closed head I), sup-ported upon Wheels to run back and forth on thervalve seat or on Ways parallel thereto and reeeiving a piston C, attached rigidly to the 10 valve, and thereby being caused to travel With the Valve and relieve it of all pressure of steam beyond What is necessary to con fine the Valve to its seat. f

WM. BURDON. Witnesses:

WM. TUsoH,

JAMES F. BUCKLEY. 

